Security labels including tamper evident labels are needed for many diverse and numerous applications. For instance, such labels can be used to seal containers, envelopes, and other products in order to protect the items prior to use. Tamper evident labels can also prevent the labels from being transferred from an authorized product to an unauthorized product, such as a counterfeit product.
In the past, many security labels and tamper evident labels have included relatively complex constructions. For instance, security labels have been back-printed, generally after metallisation of a film to provide areas of differential adhesion of the metallisation to an adhesive layer. In these constructions, upon attempted removal of the label, the bond of the metallised layer to an adhesive layer is less than the bond of the adhesive layer to an article. In this manner, portions of the metallised layer are left on the adhesive layer when there is an attempt to remove the label. These differential tear effect areas can be used to reveal messages upon removal of the tamper evident label by leaving a variable metal pattern adhered to the adhesive on the article.
As can be appreciated, the above labels are made using many process steps, can include many different layers of materials, and be made from relatively expensive materials. Thus, a need currently exists for a tamper evident label that is relatively simple to produce and manufacture.